The present invention relates to a flexible receptacle for fluids, which receptacle comprises a substantially cylindrical outer casing and an inner bag positioned within said casing, said bag being provided with filling and emptying means, whereby said casing is formed by a hose which is doubled up at one end of the receptacle so as to obtain an outer casing with a double wall.
It is previously known to transport fluids, such as juice, cooking oil and wine, in large flexible receptacles of plastic, which receptacles are enclosed in a container during transportation. The receptacles are made of a fabric of high strength properties and impermeable to liquids and gases, which fabric is provided with an opening for a filling and emptying valve. Known receptacles involve such a high price that only if the same receptacle is used several times could this way of transportation be regarded as profitable. Consequently, the receptacle must be washed after having been emptied, then folded up and returned to the place of delivery to be refilled there.
Attempts have been made to produce disposable receptacles so as to avoid the above-mentioned steps which increase costs. Such receptacles consist of an outer casing of a durable material and an inner bag of a thin material, to which bag the filling and emptying valve is attached. The outer casing is provided with an opening for the valve. A problem which has prevented wide use of this kind of disposable receptacle is that the receptacles must be inexpensive but nevertheless of such a durability that they meet the requirements made of receptacles of this type.
It is previously known to manufacture large sacks for bulk goods by passing a hose-shaped circular fabric through a relatively small ring until the ring is positioned in the middle of the fabric and thereafter folding back that portion of the fabric which has been passed through the ring over the other portion, whereafter the end portions of the fabric are bound together with a knot. In this way, a sack is obtained which has a double wall and is very durable on account of the double wall and the absence of seams.
A sack manufactured in this way, however, has certain disadvantages. One disadvantage is that when the sack is filled, the ring is exposed to high radial forces directed outwards, which requires a high durability from the ring. The disadvantage is particularly prominent if the sack is replaced by a receptacle which is filled with a pressurized liquid. Another disadvantage is that the contact surface between the ring and the fabric extending therethrough exceeds 180.degree.. As the fabric is pressed against the ring with a high force when the sack is full, a high friction is created between the ring and the fabric, which to a great extent prevents the fabric material from sliding through the ring. This prevents equalization of the stresses in the outer and inner walls of the sack when the sack is being filled up and when it is exposed to strains during transportation. In addition, folding up the fabric around the ring subjects the longitudinal warp threads of the fabric to a breaking effect which together with the high friction between the fabric and the ring easily causes breaking of the warp threads.